**6. Disadvantages of vertical farming**

*Urban Horticulture - Necessity of the Future*

organization, has reported in an article that a new aeroponic system originated in Singapore can provide a solution to this difficulty. Traditional aeroponic method involved cold nutrient mixture that used to be sprayed onto the plant roots, thereby lowering the temperature causing wilting and ultimately death of the plant. But this type of cooling is expensive, even for rich cities like Singapore. To overcome this limitation, in the year 2004, Gregory Chow, lecturer at the Ngee Ann Polytechnic of Singapore invented the air dynaponics—a much less costly way of maintaining low root-zone temperatures for commercially successful aeroponics. This system gave positive outcomes. Researchers stated that the nutrients infused with oxygen "energized" the entire root system and improved the plant top biomass. Air dynaponics uses the cooling methods of Venturi nozzle effect in an air-powered operation that lowers the temperature of the nutrient mixture and supplies air from the dissolved oxygen. In Singapore, this method is used to produce valuable greens like butterhead lettuce, Batavia lettuce, and Romaine lettuce for moneymaking purposes [14].

**4.4 Vertical farming systems can be further classified on the basis** 

These are the types of vertical farms constructed in abandoned buildings in urban areas. For example, Chicago's "The Plant" vertical farm was constructed in an old pork-packing plant. Vertical farms are also constructed in new buildings. A new multistory vertical farm is built to an existing parking lot structure in downtown Jackson Hole, Wyoming. Here, vegetables are grown throughout the year in the 13,500-square-foot hydroponic greenhouse for sale to restaurants, to local grocery

These types of vertical farms are becoming popular day by day. They use 40-foot

Despommier mentioned a number of environmental and social advantages in his book called "The Vertical Farm: Feeding the World in the 21st Century." The

• Vertical farming ensures production of greens all year round in nontropical countries and is better than normal farming. Despommier stated that 1 acre of vertical farm can produce products almost equal to the amount of products produced by 30 acres of normal farmland on considering the number of crops

• Vertical farming involves reduction or abandonment of the use of herbicides and pesticides. In some cases, vertical farming uses ladybugs and other biologi-

shipping containers that carry goods around the world and house vertical farms with LED lights, drip irrigation systems, and vertically stacked shelves for growing a variety of plants. It contains computer-controlled growth management systems that allow users to examine all systems from a smartphone or computer. The three leading companies producing shipping-container vertical farms are Freight Farms,

**of structure that houses the system**

stores, and also directly to consumers [12].

*4.4.2 Shipping-container vertical farms*

CropBox, and Growtainers [12].

**5. Advantages of vertical farming**

advantages are summarized below [15]:

produced each season.

cal controls when required.

*4.4.1 Building-based vertical farms*

**162**

Apart from so many advantages, there are many critics of the vertical farming described by the scientists. They claimed that there are a number of problems in vertical farming. The challenges to vertical farming may be summarized as follows [13]:


## **7. World-wide implementation of urban agriculture/vertical farming**

Scientists explored the motivations for urban gardening in Germany by screening 657 urban gardening project websites and characterized the types of gardeners, cultivation methods, and consumer behavior. The study also highlighted the "terrabioponic smart-garden system" where the plants grow in natural soil and in organic nutrient solution, which may facilitate social transition toward bio economy [16]. Also scientists from the United Kingdom reported that vertical farming system has increased the yield of lettuce per unit area as compared to traditional horizontal hydroponics [17]. Agriculture and food production activities in the cities of Mexico can contribute in reducing carbon footprint by creating green environment and better land use [18].

**Case study 1:** The world's largest indoor vertical farm, AeroFarms, is located in Newark, New Jersey, which grows more than 2 million pounds of greens per year without sunlight, soil or pesticides. Instead of using a huge quantity of water to grow plants, AeroFarms system sprays nutrient-rich mist to the plants. Seeds are sown, germinated, and grown on reusable sheets of cloth and are stretched out over trays stacked vertically. LED lights are used instead of the sun, and the exposure is controlled depending upon the maturity of the plant [12].

**Case study 2:** Rob Laing founded Farm.One in the year 2016 in order to grow rare and hard-to-find produce to the chefs and restaurants in the middle of New York City. The first farm was set up at the Institute of Culinary Education (ICE) in downtown Manhattan, and the second farm is in Tribeca. It uses hydroponics and LED lights and aims to grow rare produce every year. The company supplies rare herbs, edible flowers and microgreens to some of the best chefs in New York [19].

**Case study 3:** One of the world's first commercial vertical farms named Sky Greens was built in Singapore. This vertical farm produces one ton of vegetables every other day. Large varieties of tropical vegetables like Chinese cabbage, spinach, lettuce, xia bai cai, bayam, kang kong, cai xin, gai lan, and nai bai are grown. Sky Greens uses a hydraulic system called "A Go-Gro," which consists of 6-m-tall hydraulic waterdriven A-shaped towers. Each tower contains 22–26 tiers of growing troughs, and is spun around the aluminum frame at a speed of 1 mm/sec for a steady radiation of sunlight, proper air flow, and irrigation for all the edibles growing in the tower. The rotation system is powered by a unique gravity-aided water-pulley system that uses only 1 L of water per 16-hour cycle, which is collected in a rainwater-fed reservoir. The water used in powering the frames is recycled and filtered before returning to the plants. The organic wastes produced on the farm are composted and reused [19].
